Improvement in speaking-tubes



glatt@ gieten gatrat @ffice IMPROVEMENT IN SPEAKING-TUBES.

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TO ALL WHOM IT MAY CONCERN:

Beit known that I, J. B. SHANNON, of Philadelphia, Pennsylvania, have invented an Improvement in Mouth- Pieces for Speaking-Tubes; and I do hereby declare the followingto be a full, clear, and exact description of the same. v

My invention consists of a flap or plate, hinged to t-he cover of the mouth-piece of a speaking-tube us described hereafter, so that on blowing through the tube it will be caused to fall or to swing to one side, thereby indicating, when a number of tubes are arranged together, the one from which the signal has proceeded.

In order to enable others to make and use my invention, I will now proceed to describe itsconstruction and operation, reference being had to the accompanying drawing, which forms a. part of this specification, and in which- Figure 1 is a vertical section of my improved mouth-piece for speaking-tubes.

Figure 2, an exterior view of the same.

Figure 3, a view of the mouth-piece with the'cover depressed.

Figure 4, a frontview.

Figure 5, a modification of my invention; and

Figure 6, a view of an ordinary mouth-piece.

Similar letters refer to similar parts throughout the several views.

A is the mouth-piece, of cast iron, sheet metal, or other suitable material, the cylindrical portion a of which is secured to an ordinary speaking-tube. 'lo a projection, b, on the under side of the mouth-piece, isliinged the cover B, provided with a ange, c, by means of which it is held in an elevated position against the front ofthe mouth-piece, as shown in tig. 1. Secured to the inner face of the cover B is an alarm-whistle, C, the holes in which are concentric with a larger opening, d, in the cover. A light sheet-metal plate, D, the upper concave portion e of which is arranged to close the openingd, is so hinged to a small projection on the lower part of the cover B that, when placed against the t'uce of the latter, it will remain in an elevated position, but so that a slight current of air from the tube will be suiicient to cause it to fall to the position shown in fig. 2.

When a numberv of mouth-pieces connected with speaking-'tubes is arranged side by side, as is often the case in large buildings, and the whistle is sounded to attract attention, it is a difficult matter to discover from which tube the sound proceeds. To remedy this defect the device illustrated in iig. 6 has been adopted. In this case the whistle isvsecured to the top of a box at the rear of the mouth-piece, and its opening covered by a horizontal hinged ap,z'. When the whistle is sounded the flap a.' rises, and sometimes falls back to the position shown in dotted lines,'thus indicating the tube from which the sound has proceeded; but as the flap sometimes rises and then falls to its first position, the device is unreliable. In order to vprevent this I construct the mouth-piece, as above described, so that the slightest current of air blown through the tube and whistle is 'suticient to cause the plate D to fall, in which position it will remain until returned to its proper place. When it is desired to speak through the tube the cover B is turned upon its hinge and depresscd,as shown in fig. 3.

In the modilication ofvxny invention, shown in fig. 5, the pla-te D is hinged at one side of the cover B, so

that it will open laterally, the mouth-piece being suilicicntly inclined to prevent it from returning to its place.V

I claim as my invention, and desire to secure by Letters Patent- The Hap or plate D, hinged to and arranged ou the corner of the mouth-piece A in respect to the opening din the said cover, as und for the purpose set forth.

In testimony whereof' I have signed my name to this specification in the presence of two subscribing witnesses.

J. B. SHANNON.

Witnesses:

CHARLES E. Fosree, JOHN WHITE. 

